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What are discrete spheres?
刘世平 教授(中科大)
Wednesday, November 14th, 2018, 12:30 PM 闵行4教414 

Abstract: The BonnetMyers theorem states that an ndimensional complete Riemannian manifold M with Ricci curvature lower bounded by a positive number (n1)K is compact, and its diameter is no greater than $\pi/\sqrt{K}$. Moreover, Cheng's rigidity theorem tells that the diameter estimate is sharp if and only if M is the ndimensional round sphere. In this talk, I will discuss discrete analogues of round spheres in graph theory via exploring discrete BonnetMyersCheng type results. This talk is based on joint works with Cushing, Kamtue, Koolen, Muench, and Peyerimhoff.



